1-(4-Amino-2-sulfophenyl)-3-carboxy-5-pyrazolone 1-(4-Amino-2-sulphophenyl)-4,5-dihydro-5-oxo-1H-pyrazole-3-carboxylic acid 1H-Pyrazole-3-carboxylic acid, 1-(4-amino-2-sulfophenyl)-4,5-dihydro-5-oxo- 70616-71-6 EINECS 274-699-8